Can the Ratio of Chin-neck Circumference and Neck Circumference to Chin-neck Circumference Predict Difficult Intubation in Obese Patients? (intubation)

Importance and Purpose of the Study: Proper management of the difficult airway is an important part of preventing anesthesia-related mortality and morbidity. Difficult airways, characterized by both difficult mask ventilation and difficult intubation, are common in obese patients. Many studies have shown an association between obesity or morbid obesity and difficult intubation. We thought that in obese patients, increased subcutaneous fat tissue in the nape of the neck may restrict the head extension and cause difficult intubation and difficult mask ventilation, and the increase in the chin-nape circumference may predict difficult intubation and difficult mask ventilation. We also predicted that the ratio of neck circumference to chin-nape circumference might predict difficult intubation and difficult mask ventilation.

Materials and Methods: After the approval of the ethics committee, obese patients who require tracheal intubation, undergo elective surgery, over the age of 18, with a body mass index (BMI) of more than 30 were evaluated. Patients with cervical spine anomaly, emergency procedures, known history of difficult intubation or upper respiratory tract disease, and planned awake intubation were excluded from the study. Mallampati score, mouth opening, upper lip bite test, distance between incisors, thyromental distance, sternomental distance and thyromental height were recorded. Using a tape measure, the neck circumference from the thyroid cartilage level and the chin-neck circumference from the mentum level were measured with the patient in a neutral position. The ratio of neck circumference to thyromental distance and the ratio of neck circumference to chin-nape circumference were calculated from these measurements. Mask ventilation was graded according to the method described by Han et al. After adequate muscle relaxation was achieved, tracheal intubation was performed with an appropriately sized Macintosh blade using direct laryngoscopy. Difficult intubation evaluation was performed using the Difficult Intubation Scale (IDS) based on seven variables.

Results: A statistically significant relationship was found between difficult intubation and the distance between incisors, neck circumference, neck circumference / thyromental distance, neck circumference / sternomental distance, and chin-nape circumference. In the multivariate regression analysis performed with these parameters, the distance between the incisors was <4.85 cm and the neck circumference> 41.5 cm was found to be independent risk factors for difficult intubation. A statistically significant relationship was found between difficult mask ventilation and age, male gender, OSAS, neck circumference, neck circumference / thyromental distance, neck circumference / sternomental distance, neck circumference / chin-nape circumference and chin-nape circumference. In the multivariate regression analysis performed with these parameters, it was determined that male gender and neck circumference thicker than 45.5 cm were independent risk factors for difficult mask ventilation.

Conclusion: The ratio of neck circumference to chin-nape circumference and chin-nape circumference are successful in predicting difficult mask ventilation in obese patients. While chin-nape circumference is successful in predicting difficult intubation in obese patients, neck circumference / chin-nape circumference is unsuccessful.

Study Overview

• Status: Completed
• Conditions: Difficult Airway Intubation; Obesity Adult Onset
• Intervention / Treatment: Other: intubation; Other: mask ventilation

• Study Type: Observational
• Enrollment (Actual): 4

Contacts and Locations

Study Locations

• Turkey
  • Ankara, Turkey, 06000
    • Keçiören Training and Research Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

• Sampling Method: Probability Sample

Study Population

Patients who will be operated under general anesthesia with endotracheal intubation, aged 18 years and over, with body mass index (BMI≥30) and ASA 1-3

Description

Inclusion Criteria: Patients who will be operated under general anesthesia with endotracheal intubation, aged 18 years and over, with body mass index (BMI≥30) and ASA 1-3

Exclusion Criteria:Patients with cervical spine anomalies, emergency procedures, known difficult intubation history and awake intubation plan, and those with beard were excluded from the study.

Study Plan

How is the study designed?

Design Details

• Observational Models: Case-Control
• Time Perspectives: Prospective

Number of groups / cohorts

4

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
difficult intubation; patients with a difficult intubation score of 5 or more	Other: intubation; intubation
easy intubation; patients with difficult intubation score less than 5	Other: intubation; intubation
difficult mask ventilation; group 3 and 4 by han mask ventilation grouping	Other: mask ventilation; mask ventilation
easy mask ventilation; group 1 and 2 according to han mask ventilation grouping	Other: mask ventilation; mask ventilation

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Parameters associated with difficult intubation in obese patients	mallampati score, cormack-lehane score, distance between incisors, neck circumference, ratio of neck circumference to thyromental distance, ratio of neck circumference to sternomental distance and chin-nape circumference	always

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
parameters associated with difficult mask ventilation in obese patients	age, gender, OSAS, neck circumference, chin-nape circumference, ratio of neck circumference to chin-nape circumference, ratio of neck circumference to thyromental distance, and ratio of neck circumference to sternomenal distance	always

Collaborators and Investigators

• Sponsor: Kecioren Education and Training Hospital
• Investigators: Principal Investigator: adem selvi, uzman dr., sorumlu araştırmacı

Study record dates

Study Major Dates

• Study Start (Actual): September 12, 2019
• Primary Completion (Actual): February 15, 2020
• Study Completion (Actual): June 7, 2020

Study Registration Dates

• First Submitted: January 10, 2021
• First Submitted That Met QC Criteria: January 13, 2021
• First Posted (Actual): January 15, 2021

Study Record Updates

• Last Update Posted (Actual): January 15, 2021
• Last Update Submitted That Met QC Criteria: January 13, 2021
• Last Verified: January 1, 2021

More Information

Terms related to this study

• Keywords: obesity; difficult airway; neck circumference / chin-nape circumference; chin-nape circumference
• Additional Relevant MeSH Terms: Overnutrition; Nutrition Disorders; Overweight; Body Weight; Obesity
• Other Study ID Numbers: adem obez havayolu

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: Yes
• IPD Plan Description: everything
• IPD Sharing Time Frame: 6 months
• IPD Sharing Access Criteria: difficult airway obesity
• IPD Sharing Supporting Information Type: Study Protocol; Statistical Analysis Plan (SAP); Informed Consent Form (ICF); Clinical Study Report (CSR); Analytic Code

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No